The present invention relates to a device for locking the trunk lid of a motor vehicle.
Many motor vehicles have trunks with lids at their rear parts. A locking device is known which can be operated by a switch provided in the vehicle interior to unlock and release the trunk lid. One example is that disclosed in Japanese Laid Open Utility Model Publication No. 65165/1984. When the switch is manipulated, it actuates a solenoid or a motor to swing a detent lever of the locking device. As a result, a striker is released from an engagement slot formed in a latch member. Thus the trunk lid to which the striker is attached is released.
With a conventional locking device, however, the action of closing the trunk lid is resisted by a number of reactionary forces. One of these forces is that required to compress a trunk lid or a weather strip provided in the peripheral edge of the trunk lid. Another is the reaction of a spring which must be overcome by the striker being pressed into the engagement slot of the latch member to cause the latch member to rotate, and thereby engage with the detent lever.
Consequently, a great force must be applied to close the trunk lid because of the reactions of the weather strip, the spring, and so on. This has given rise to problems such as difficulty in closing the trunk lid.
Accordingly, there has previously been proposed a device for locking trunk lids of motor vehicles by which the force required to close the trunk lids is reduced. This conventional device is disclosed in Japanese Utility Model Application No. 30357/1988 filed by the present applicant.
FIG. 4 and 5 shows this conventional device. In FIG. 4 and 5, a locking mechanism 15 is secured to a rear edge part of a trunk structure of the motor vehicle. The striker 12 which engages with the locking mechanism 15 is secured to the rear edge part of the trunk lid 11. A key type unlocking mechanism 14 is secured next to the locking mechanism 15. A sensor (not shown) is provided to detect the position to which trunk lid 11 is lowered in closing motion.
On the basis of a signal from the sensor, a motor M is operated to rotate the latch member 2 by a inner cable 19. At this time, the striker is fitted in the engagement slot 2a of the latch member. The latch member is thus rotated forcibly and moves the striker far into a guide slot formed in the base plate of the device. Then, the latch member is caught and stopped by the detent lever 6. The inner cable 19 returns to a first position by operating the motor M in the reverse direction.
On the other hand, the motor M is operated in the reverse direction on the basis of unlocking signals from the key type unlocking mechanism or from a lid opening switch (not shown) provided in the vehicle interior. The detent lever 6 swings and is then released from the latch member 2. The inner cable returns to the first position by operating the motor M in the forward direction. As mentioned above, when the trunk lid is closed, the latch member is driven by the motor and forcibly moves the striker down. The lid closing force is therefore reduced. On the other hand, when the trunk lid is opened, the motor M is operated in the reverse direction to rotate the detent lever through the inner cable. The detent lever swings and is released from the latch member.
In spite of the improvement afforded by the above described locking device, the following problems remain.
Cables are provided in the latch member and in the detent lever respectively. The locking operation or the unlocking operation of the locking device are made through the cables by operating the motor in the forward or reverse directions. The structure of the locking device is therefore complicated, and the problem of the lack of reliability of the mechanical operation remains because it is required to provide escape slots both in the connecting portion between the latch member and the cable, and in the connecting portion between the detent lever and the cable.